Crimped polyester filaments



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CRIMPED POLYESTER FILAMENTS Filed May 2, 1966 FIGI FIGQ

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United States Patent Oce 3,381,057 Patented Apr. 30, 1968 3,381,057 CRiMPED PLYESTER FliJAli/ENTS Tadao Senco and Yoshizo Unaya, rasalta-gaan, lnkirshimaken, Japan, assignors to Nitto Bosal-d Company Limited, Fukushima-iien, Japan, a corporation of Japan Filed May 2, 1966, Ser. No. 546,887 6 Claims. (Ci. 26d-860) ABSTRACT F THE DSCLOSURE A polyester filament composition which comprises 50- l0() parts by Weight of a highly crystalline and rapid crystallizing homopolyester selected from the group consisting of a homopolyester obtained from polymerizing 1,2-bis-(carbomethoxyphenoxy)-ethane with ethylene glycol and homopolyester being polyethylene terephthalate, and said homopolyester being blended with 40-100 parts by weight of a block copolymer resulting from the polymerization of said homopolyester with a polyethylene glycol having a molecular `weight of LOW-6,000.

The present invention relates to the manufacture of crimped polyester filaments and has particular reference to the process for producing highly crimped filaments or fibers by spinning homopolyesters together with block copolymers of said homopolyesters and polyethylene glycol.

There has been introduced a number of processes for the production of various synthetic fibers by spinning different types of polymers in a molten state.

One of the drawbacks inherent in such prior-art processes is that the filaments thereby obtained are difiicult to be crimped for the reason that the filament components are cross-sectionally homogeneous and symmetric in the chemical or physical properties.

This drawback has been overcome in one way by mechanically forcing the filaments to be crimped with use of, for example, a toothed gear-wheel- Such mechanical means, however, would provide only two-dimensional crirnps in the filaments which tend to get released with time. Another way of providing crimps in the filaments heretofore proposed is based on the discovery that heterogeneity and asymmetry of the physicochemical properties of starting polymers are conducive to the crimping effect, as this is exemplified by acryl filaments trade named Orlon 2l. Examination of the cross section of this acryl fiber shows that it comprises two distinctive regions-hydrophillic and hydrophobicwhich add to easiness of crimping.

More lately known for the preparation of highly crimped artificial filaments is a so-called conjugate-spin ning wherein two or more diffejent types of polymers are separately melted or dissolved and spun through the respective nozzles, immediately followed by combining all individual streams of polymers into a single piece of filament. This process is extremely complicated from the practical, commercial point of view and further has the disadvantage that the filaments after spun are often apt to disintegrate back into individual components.

Whereas, it is an object of the present invention to provide improved method and means for producing highly crimped filaments of this character which will eliminate theabove-noted diiculties.

It is another object of the present invention to provide highly crimped artificial filaments of this character which have excellent fastness to light, color, wash and sublimation, good afiinity to dye and other requisite properties for fibers and fabrics.

These and other advantages and features of the present invention will be more apparent from the detailed description which follows in conjunction with a few preferred embodiments of the inventive concept, a reference being had to the accompanying drawings wherein:

FIG. l is a schematic illustration revealing the crosssectional features of the filament of the present invention as observed under a microscope, and

FIG. 2 graphically displays the residual tenacity and elongation factors of the filament of the present invention as plotted against time of light exposure irradiation.

The present inventors have discovered that polyester filaments of such desired properties as set forth in the above objects of the invention may be obtained by blending two or more polymeric materials which are cosoluble but significantly differ from each other in the crystallinity and velocity of crystallization.

It has Ibeen further discovered that some components of such polymer mixture melt and mingle uniformly with other components but tend to crystallize faster than the latter when extruded through a nozzle. This is because the former component polymers have remarkably higher crystallinity and faster crystallization tendency than the latter. The use of two or more of these characteristically different polymers gives intensive crimps to the resulting filaments, the form of such crimps being substantially helical according to the present invention.

The higher crystallinity and faster crystallization type of polymer according to the invention may preferably be polyethylene terephthalate or a polyester resulting from the reaction of 1,2-bis-(carbomethoxyphenoxy)-ethane with ethylene glycol. Whereas, the lower crystallinity and slower crystallization category of polymer may preferably be a block copolymer resulting from the polycondensation of dimethyl terephthalate and ethylene glycol to form polyethylene terephthalate in the presence of polyethylene glycol. The structural formula of this block copolymer is 1 \ooH2CH2/ n (2) where m and n represent polymerization degrees, and this polymer contains 10%-60% by weight of the polyethylene glycol component (2).

Another example of block copolymer according to the invention may be obtained from the polycondensation of l,2bis(carbomethoxyphenoxy) ethane and ethylene glycol to form a polyester in the presence of polyethylene glycol. This is represented by the structural formula:

(Il) io@-0entorno-@ ooooornorno substantially helical form, the number of crimp Waves increasing to about l to 20.

Example 4 A white block copolymer was used which was the same as used in Example 1 except that 70 parts by Weight of dimethyl terephthalate were polymerized With 30 parts of polyethylene glycol. This block copolymer having a specific viscosity of 1.650 and a melting point of 240-243 C. was pelletized to a size measuring 2 mm. in diameter and 3 mm. long.

50 parts by Weight of these pellets were admixed with 50 parts of polyethylene terephthalate pellets and spun in the manner described in Example 3. The resulting filament, when stretched by four times, revealed 5 to 10 helical crimp Waves per mm. length. llt was further eated to 100 C. for about 10 minutes thereby increasing the number of crimp waves to about l5 to 20. The thus thermally set filament was tested to show a fineness of 5.32 deniers, a tenacity of 3.37 grams per denier, an elongation of 44.5%, an average number of crimp Waves amounting to 15.8 per 10 mm. length and a crimp elasticity of 73.4%.

Since the invention has been described in some detail as to a few specific embodiments thereof, it will be understood that certain changes and adaptations may be made as obvious to those skilled in the art Without departing from the accepted claims in which it is the intention to claim all novelty inherent in the invention as broadly as is permissible in View of the prior art.

What is claimed is:

1. A polyester filament composition comprising 50-100 parts by Weight of a highly crystalline and fast crystallizing homopolyester, selected from the group consisting of polyethylene terephthalate and the polyester obtained by polymerizing 1,2-bis-(canbomethoxyphenoxy)-ethane with ethylene glycol, blended with 40-100 parts by Weight of a block copolymer resulting from the polymerization of said homopolyester with a polyethylene glycol having a molecular Weight of 1,000-6,000.

2. A polyester filament as defined in claim 1, wherein said homopolyester is obtained from polymerizing 1,2-bis- (carbomethoxyphenoxy)-ethane with ethylene glycol.

3. A polyester filament as defined in claim 1, wherein said homopolyester is polyethylene terephthalate.

4. A process for the production of highly crimped polyester tilaments comprising pelletizing 100 parts by weight of a block copolymer resulting from the polymerization of 1,2-bis-(carbomethoxyphenoxy)-ethane, ethylene glycol andpolyethylene glycol having a molecular Weight of l,500-3,000, admixing said block copolymer with 100 parts of similarly pelletized homopolyester resulting from the polymerization of 1,2-bis-(canbomethoxyphenoxy) ethane and ethylene glycol heating the admixture to 260- 280 C. and melt spinning thereby producing sharply crimped filaments and thermally setting said filaments at 100 C.

5. A process for the production of highly crimped polyester filaments comprising pelletizing 40 parts by Weight of a block copolymer having a specific viscosity of 1.653 and a melting point of 226-230 C. resulting from the polymerization of 1,Z-bis-(carbomethoxyphenoxy)-ethane, ethylene glycol and polyethylene glycol having a molecular weight of 1,500-3,000, admixing same with parts of similarly pelletized homopolyester resulting from the polymerization of 1,2-bis-(carbomethoxyphenoxy)-ethane and ethylene glycol, heating the admixture to 260-280 C. for melt spinning thereby producing sharply crimped filaments and thermally setting said filaments at C. for about 10 minutes.

6. A process for the production of highly crimped polyester filaments comprising pelletizing 40-5() parts by weight of a block copolymer having a specific viscosity of 1.650-l.831 and a melting point of 238-243 C. resulting from the polymerization of dimethyl terephthalate, ethylene glycol and polyethylene glycol having a molecular weight of G-3,000, admixing same with 40-60 parts of similarly pelletized polyethylene terephthalate, heating the admixture to 260-280 C. for melt spinning thereby producing sharply crimped filaments and thermally setting said filaments at 100 C.

References Cited UNITED STATES PATENTS 2,836,576 5/1958 Piccard et all 260-860 3,013,914 12/1961 Willard 164-43 FOREIGN PATENTS 777,574 6/ 1957 Great Britain. 956,833 4/ 1964 Great Britain.

MURRAY TILLMAN, Primm-y Examiner.

JOHN T. GOOLKASIAN, Assistant Examiner. 

